EXTRACORPOREAL HEPARIN ADSORPTION FOLLOWING CARDIOPULMONARY BYPASS WITH A HEPARIN REMOVAL DEVICE - AN ALTERNATIVE TO PROTAMINE

Objectives: To evaluate the therapeutic efficacy and applicability of a heparin removal device (HRD) based on plasma separation and poly-l-l ysine (PLL) affinity adsorption as an alternative to protamine in reve rsing systemic heparinization following cardiopulmonary bypass (CPB). Design: A prospective study. Setting: University research laboratory. Subjects: Adult female swine (n = 7). interventions: Female Yorkshire swine (n = 7, 67.3 +/- 3.5 [SEM] kg) were subjected to 60 mins of righ t atrium-to-aortic, hypothermic (28 degrees C) CPB, After weaning from CPB, the right atrium was recannulated with a two stage, dual-lumen c annula which was connected to an HRD via extracorporeal circulation. B lood flow was drained at 1431.2 +/- 25.4 mL/min from the inferior vena cava, through the plasma separation chamber of the HRD (where heparin was bound to PLL), and reinfused into the right atrium. The HRD run t ime was determined by a previously established mathematical model of f irst-order exponential depletion. Measurements and Main Results: Heart rate, mean arterial pressure, pulmonary arterial pressure, central ve nous pressure, kaolin and celite activated clotting time (ACT), activa ted partial thromboplastin time (APTT), heparin concentration, and pla sma free hemoglobin were obtained before, during, and after the use of the HRD. Pre-CPB ACT was 167 +/- 89 sees (kaolin) and 99 +/- 7 sees ( celite), and APTT was 34 +/- 5 sees. The HRD run time averaged 27.4 +/ - 1.5 mins targeted to remove 90% total body heparin. Use of the HRD w as not associated with any adverse hemodynamic reactions or increases in plasma free hemoglobin. The heparin concentration immediately follo wing CPB was 4.85 +/- 0.24 units/mt, with ACT >1000 sees and APTT >150 sees in all animals. During heparin removal, total body heparin conte nt followed first-order exponential depletion kinetics. At the end of the HRD run, heparin concentration decreased to 0.51 +/- 0.09 units/mt , with kaolin ACT returning to 177 +/- 22 sees, celite ACT returning t o 179 +/- 17 sees, and APTT returning to 27 +/- 3 sees (p >.05 vs. pre -CPB baseline far all variables). Conclusions: The HRD is capable of r eversal of anticoagulation following CPB without significant blood cel l damage or changes in hemodynamics. The HRD, therefore, can serve as an alternative to achieve heparin clearance in clinical situations whe re use of protamine may be contraindicated.